Presently, users wishing to interact with a computer system typically do so via a keyboard and/or mouse. Whilst such interface systems are useful, they are relatively bulky, and lack the tactile nature of using, say, a pen on paper. In terms of legibility and comfort, information delivered on paper is more physically comfortable and convenient, due to its visual characteristics and its portability compared to computer keyboards and other computer interface devices. However, unlike mouse and keyboard input systems, pen and paper generally lack the ability to control computer software.